Oil burner



R. C. GROLL Oct. 30, 1962 OIL BURNER 5 Sheets-Sheet l Filed Sept. 25,

Inventar: /aoarf C. GFO/ A-rTocLN s55 A R. C. GROLL Oct. 30, 1962 OIL BURNER 5 Sheets-Sheet 2 Filed Sept. 25, 1958 R. C. GROLL OIL BURNER 5 sheets-sheet 5 Filed Sept. 25, 1958 ATTO [LNESS United tares @arent 3,060,999 6H. BURNER Robert C. Groll, 1 Aitaderneistrasse, Munich, Germany Filed Sept. 25, 1958, Ser. No. 763,408 Claims priority, applicaticn Germany Get. 11, 1957 Claims. (Cl. 15S- 91) The present invention relates to an oil burner comprising a combustion chamber and a gasifying and cracking chamber, oil supply means preferably `arranged adjacent the bottom end of said gasifying chamber, at least one of the walls of said gasifying chamber defining `a hollow cylinder provided with air inlet openings for the igasifying flames, and `a partition wall between said combustion chamber and said gasifying chamber, which is provided with a nozzle-like opening connecting the gasifying chamber with the combustion chamber.

In burners of this type of the danger of explosion-like combustion is reduced by the gasifying chamber being formed as a hollow cylinder or the like, but for proper operation these burners still largely depend on the draught of the existing chimney. A further disadvantage of the known types of burners resides in the fact that they tend to become sooted after a relatively short time and must therefore be frequently -cleaned which .is very disagreeable and tedious. It must also be mentioned that in burners of the kind referred to there is considerable danger of the ame being blown out, for example by gusts of wind in the chimney, and the combustion efficiency and therefore the fuel consumption, is unsatisfactory due to insufficient gasification of the fuel.

It is an object of the present invention to obviate these drawbacks and .to provide for this purpose a burner of the kind above referred to, the main feature of which resides in the fact that the gasifying and cracking charnber is subdivided into at least one spiral duct with any suitable number of coils, which opens into a centrifugal chamber arranged coaxial with the nozzle and directly below the latter. Whereas in the known burners the Way of the oil to the :burner nozzle is very short so that the oil is only evaporated, the arrangement according to the invention results in long heating-up paths due to the `spiral duct or ducts, leading to a cracking of the oil, which fundamentally diers from an evaporation thereof. It should be noted in this connection that in the burner of the present invention liquid oil is first gasiiied, then changes its molecular structure by a cracking process, is diffused with air `and finally is ignited. Thus the oil is subjected to physical changes in the lower portion -of the burner yand to chemical changes in the upper portion of the burner. This, however, is not the only advantage, ibut a high ow velocity of the gases is obtained, even in burners `of low construction, due to the long heating-up path and the resulting great temperature differential between the upper and lower zone of the burner. This high flow velocity `of the gases has a blower-like effect on the chimney `so that also in the case of bad draught conditions in the chimney, proper functioning of the burner is assured. This blower effect has the further advantage that the ame can be extinguished neither by strong gusts of Wind -nor by the quick opening of doors. Whether one, two or three spiral ducts are provided, and whether Ithe number of coils is increased, is determined by the existing draught conditions, by the required flame temperatures, and by the overall height of the burner. The opening of the duct or ducts into a centrifugal chamber presents the advantage that the soot particles which according to experience form only in the cold zones, are kept olf the nozzle due to their mass inertia and due to centrifugal force until they have been burned, i.e. until their mass has ybeen reduced, which requires about 6 to 8 seconds.

fIn the case `of the present `oil burner this means that the soot particles which may have formed in the oil supply zone are drawn upward :by the turbo effect, and due to their mass will keep in the outermost peripheral zone of the centrifugal chamber where they glow away, Whilst the oil which in the long heating-up path has been completely gasied, travels towards the nozzle with a rotary movement and through this nozzle enters the combustion chamber where it burns with a non-sooting, very hot and particularly lively flame. Combustion is also improved by the gases expanding after their rotary passage through the nozzle, which is due to the fact -that the increase of the rotational speed within the centrifugal chamber towards the core of the nozzle, results in a storing `of energy in the core zone, which subsequently acts in an outward direction.

According to a further feature of the invention the spiral ducts are `formed by flanges which are spirally arranged 0n an insert element and may, for example, be made of sheet metal strips. This construction is very cheap because it requires yonly Welding or casting operations.

The spiral ducts mentioned above may, according to the invention, be provided also by spirally winding one, two or more tubes and fixedly connecting the adjoining tube sections with each other. In comparison to the constructions described in 4the foregoing, this arrangement has the advantage that no inserts and casings are required for forming a hollow gasifying chamber. When the spiral ducts are made from tubes the arrangement preferred is one in which the air inlet openings lfor the gasifying flames are directed obliquely upward because thereby the gasifying flames will accelerate the gas ovv.

In -the interest of `a good and complete combustion it is of advantage, according to the invention, to provide the wall incorporating the nozzle with ya baiile which in combination with the wall 4forms an air duct isuing from -a cold zone. The ducting of the :air thereby results in a transverse flow in ia direc-tion towards the gas issuing from the nozzle, so that the gas is intermixed with combustion air all the Way through to the core zone thereof and complete combustion is assured. The flame zone starts at the nozzle and extends only upwardly. If necessary, the ducting of the air may be so :arranged that the air will cool the partition wall, which may be of advantage vvith gas temperatures above 1000 C., in order to obtain a good combustion. The bat'rle yand the nozzle wall also enclose -between them an air cushion -which has `an insulating effect during heating-up and facilitates the beating of the burner to the operating temperature.

According to a further advantageous feature of the present invention the supply of the air for the transversely directed flames, as well as of the combustion air for the burner nozzle proper, and of the supplementary air supplied to the produced gas, is controllable in a manner known per se, by means of rotary slide or sleeve valves which presents the very important advantage that it is always possible for the user of the burner according to the invention, to adapt the burner on the one hand to the existing draught conditions of the chimney, and on the other hand to accelerate the heating of a room, or to throttle the burner as desired.

According to the invention the gasifying chamber which is yof substantially annular cross section, may diverge conically from bottom to top and the correspondingly shaped insert may be lifted manually or automatically, for example by means of a bimetal element, possibly with the interposition of a suitable linkage or lever arrangement. This embodiment of the burner according to the invention is of particular advantage in the case of larger burners, because with such burners it may happen that during heating-up the ignition of gas at the i 3 burner nozzle is retarded by the long spiral ducts. In the last described arrangement' this danger is eliminated because when the insert is lifted (when a bimetal element is used, it .is in the raised position when the burner is cold), there is opened a gap through which the flames may propagate upwardly to the burner nozzle. If it is desired to avoid the necessity of lifting the insert, it is also possible to provide an ignition tube which bypasses the spiral ducts.

A further improvement is obtained according to the invention by providing the burner with fresh air supply means which open into the burner nozzle cross section. In this manner a burner is provided which presents very favourable conditions for a complete combustion of the fuel. The air supply tube opening into the burner nozzle cross section has the effect that the llame issuing from the burner nozzle is supplied with suiiicient oxygen not only from the outside but also from the inside, so that the flame does not only burn Without any formation of soot, but also has its temperature increased still further, so that the new burner according to the present invention has an excellent heating efficiency with a very low fuel consumption.

According to the invention the fresh air supply tube traverses the burner from the lower to the upper end thereof; this tube is not only simple in installation, but also very cheap, so that in spite of the improved efciency of operation there is practically no increase in the cost of manufacture and material. l In order to obtain an optimum distribution of the fresh air, it is of advantage according to the invention to provide the end of the tube projecting into the burner nozzle cross section, with radial and possibly also with frontally arranged axial bores in the manner of a spray head which, however, does not exclude that the tube projecting into or extending up to the nozzle cross section, is provided adjacent its upper end with guide surfaces or baiies which extend outwardly from its periphery in the same direction and shield the air outlet openings.

The effect of the gas streams on the fresh air will be quite clearly understood when the arrangement is compared with the generally known Water jet pumps: the main effect is that of the rotational energy.

The guide surfaces or baffles mentioned above may according to the invention be in the form of tongues bent outwardly from the wall of the tube, preferably in a slightly upward direction. These bafes may, if desired, be completed to ducts or channels by upper and lower screening surfaces or side Walls. Making the baflies in the form of tongues punched out of the material of the tube presents economic advantages, whereas the screening of the tongues on the sides thereof results in an arrangement which prevents the formation of vortices which would hinder the fresh air to flow out of the tube or to be drawn out therefrom.

However, according to a further feature of the present invention, the tube may also be formed as a nozzle at the outlet end thereof. Conveniently, the air inlet end of the tube is further provided with a valve, for example in the form of a rotary sleeve valve, since with such an arrangement the supply of combustion air vto the inner zones of the flame may be controlled in a simple and easy manner.

The invention will now be described in more detail with reference to the accompanying drawings in which various embodiments are shown which are given by way of example only.

In the drawings:

FIG. 1 is a sectional side view of a burner according to the invention;

FIG. 2 shows a modification of the embodiment illustrated in FIG. 1, also in sectional side view;

FIG. 3 is a side view of another modification, partly in section and with parts broken away;

FIG. 4 shows in diagrammatic form a modication of the burner shown in FIG. l;

FIG. 5 is a sectional side view of an oil burner with fresh air supply means;

FIG. 6 shows a modified detail of FIG. 5 in sectional view;

lFIG. 7 illustrates a further modification of this detail; and

FIG. 8 is a cross sectional View taken along line VIII-VIII of FIG. 7.

As shown in FIG. 1 of the drawings, a burner 1 comprises a combustion chamber 2 and a gasifying chamber 3. The gasifying chamber 3 is dened by a pot-shaped element 4 which on its upper extremity carries a partition wall 5 which extends to the inner periphery of an outer casing 6 and fills the interior thereof. Arranged inside the gasifying chamber 3 is a closed insert 7 so that between the insert 7 and the wall of element 4, remains an annular space 8 which constitutes the gasifying chamber. The peripheral wall of the pot-shaped element 4 cornprises a plurality of perforations 9 through lwhich air is aspirated for supplying transversely directed gasifying ames (not shown) with oxygen. The amount of air entering through the perforations 9 may be controlled by means of a sleeve valve 19 which according to its position opens or closes apertures 11 in the casing 6. The element 4 further carries an igniter 4socket 12 which on a hanged insert 13 carries a pivotable ilange 14 which again serves for regulating the air supply, respectively for metering the additional air which is supplied to the gas produced in the chamber 8.

The insert 7, below which discharges an oil supply tube l5, carries a helically wound flange 16 so that the chamber 8 is practically converted into a spiral duct the purpose of -which has already been explained above. The partition wall 5 is provided with a nozzle 17 and also serves as support for a baffle 18 having an opening 19'. As shown in FIGS. l, 2 and 5, small vertical pegs or projections are located between the wall 5 and the baiile 18, so that the baflie 18 is mounted on these projections. The air gap Z formed between the partition wall 5 and the air baffle 18 is connected with atmosphere through bores 21 which are adapted to be closed or opened by means of a rotary sleeve valve (not shown). A centrifugal chamber Sa is located directly below the nozzle 17.

The embodiment shown in FIG. 2 diifers from the construction illustrated in FIG. l mainly insofar, as the insert 7 comprises the perforations 9 and consequently the air for the transversely directed flames, which passes through these perforations 9, must be introduced into the insert 7. For this purpose are provided bores 22 which may be opened or closed by means of a rotary slide valve 23. The supplementary air for the gas is in this embodiment controllable by a sleeve valve 24 which opens, respectively closes, openings 25. A ring 26 is provided for preventing oil supplied through a tube 27 from flowing out through the holes 25. Heating-up of this burner is accomplished through the openings 25, and in order to provide a greater space the ring 26 maybe drawn inward to a certain extent, at least adjacent one of the holes 25, as shown in broken lines in the drawing. As compared with the construction shown in FIG. 1, this burner has the advantage that the outer casing 6 is eliminated. For the sake of simplicity and in order to facilitate understanding, like elements have been designated by like reference numerals in both figures. As may further be seen from FIG. 2, an additional sleeve valve 28 is provided for controlling the supply of combustion air to the actual heating ilame which issues from the nozzle 17 FIG. 3 illustrates an embodiment which differs from the previously described construction according to FIG. 2 mainly insofar, as the spirally wound gasifying charnber S is formed by the coils of a tube 29, i.e. the insert 7 as well as the outer casing of the gasifying chamber 8 are formed by the tubes 29 which in their inwardly directed walls also comprise the perforations 9 for the transversely directed gasifying flames. The partition wall 30 which corresponds to the wall designated by reference numeral 5 in FIGS. l and 2 is of slightly conical shape whereby the concentration of the gases in relation to nozzle 17 is rendered easier than would be the case if a flat partition wall would have been provided. The tube 29 is cut obliquely at its upper end and this upper end serves as a support for the wall 30. The chamber containing the upper end of the tube 29 is closed on all sides by metal sheets. Walls 30a enclose the chamber above the nozzle 17 Otherwise the arrangement is similar to that shown in FIG. 2.

The embodiment according to FIG. 4 is similar to that of FIG. l in its general construction, i.e. the embodiment shown in FIG. 4 differs from the other construction only insofar as the elements 4, 6, 7 present a conical shape and the element 7 is provided with a lever arrangement 311 which acts as a lifting mechanism for the purpose of by-passing the long spiral duct during heating-up of the burner, so that the inflammation length from the socket 12 to the nozzle 17 i-s reduced to a minimum.

In the embodiment shown in FIG, 5 the burner again comprises a combustion chamber 2 and a gasifying chamber 3, the latter being defined by a pot-shaped element 4 and an upper partition wall 5. In the gasifying chamber 3 there is likewise provided an insert 7 which carries a spirally wound ange 16 and defines a relatively small gasifying chamber 8. However, the entire burner 1 is traversed by a tube 32 the upper extremity of which is formed as a nozzle 33, whilst the closed lower end 34 carries a rotary valve 35 for controlling the air inlet openings 36.

FIG. 6 illustrates an embodiment in which, contrary to the construction of FIG. 5, the tube 32 is provided with radial, and frontally arranged axial bores 37 in the manner of a spray head. In the modified embodiments shown in FIGS. 7 and 8, the bores are replaced by slots 38 lwhich are formed by bending punched-out tongues 39 outwardly from the peripheral surface of tube 32. These tongues 39 act las baiiles so that gas streams owing in the direction of arrow 40 will have admixed to them suflicient quantities of fresh air from the inside. The tongues 39 may also be bent slightly upwards, i.e. to the left in FIG. 7 (not shown) so that the issuing fresh air may smoothly blend into the gas stream. As indicated by lines 41 in FIG. 8, the tongues 39 may be provided with upper and lower screening surfaces or side walls which together with the tongues 39 form ducts directed substantially parallel to the direction of flow of the gas streams.

I claim:

l. An oil burner comprising walls enclosing a combustion chamber, inner and outer coaxial cylindrical Walls defining a gasifying chamber located below said combustion chamber and other walls enclosing a centrifugal chamher located between said combustion chamber and said gasifying chamber, oil supply means substantially at the bottom end of said gasifying chamber, at least one of the walls defining said gasifying chamber being provided with air inlet openings for the gasifying flames, said other walls including a partition wall having a nozzle and separating said centrifugal chamber from said combustion chamber, and means forming in said gasifying chamber at least one helical duct, said duct being closed along lateral sides except for said air inlet openings so that gas flow is restricted to passage along the axis of the duct, said centrifugal chamber being coaxial with the nozzle.

2. The oil burner as claimed in claim l, characterized in that the helical duct is formed in part by flanges which are helically arranged on said inner cylindrical Wall, and consist of sheet metal strips, said inner cylindrical wall being part of an insert element.

3. An oil burner comprising walls enclosing a combustion chamber, means defining a gasifying chamber located below said combustion chamber, means enclosing a centrifugal chamber located between said combustion chamber and said gasifying chamber, oil supply means substantially at -the bottom end of said gasifying chamber, said second-mentioned means including a partition wall having a nozzle and separating said centrifugal chamber from said combustion chamber, the first-mentioned means comprising at least one helical duct provided with air inlet openings for the gasifying flames, said duct opening into said centrifugal chamber, said centrifugal chamber being coaxial with said nozzle, said duct being formed by coiled tubes the adjoining sections of which are xedly connected with each other.

4. The oil burner as claimed in claim 3, characterized in that said coiled tubes have air inlet openings which are directed obliquely upwards.

5. An oil burner, comprising walls enclosing a combustion chamber, walls defining a gasifying chamber located below said combustion chamber, and walls enclosing a centrifugal chamber located between said combustion chamber and said gasifying chamber, oil supply means substantially at the bottom of said gasifying chamber, the third-mentioned walls including a partition Wall having a nozzle and separating said centrifugal chamber from said combustion chamber, and means forming in said gasifying chamber at least one helical duct, said duct being closed along lateral sides except for air admission perforations in the second-mentioned walls so that gas ow is restricted to passage along the axis of the duct, said oil burner being characterized in that the walls are of substantially annular cross-section and diverge conically from the lower to the upper end thereof, one of the second-mentioned Walls being a part of an insert, and means for raising said insert.

6. An oil burner, comprising walls enclosing `a co1n bustion chamber, Walls defining a gasifying chamber located below said combustion chamber, and walls enclosing a centrifugal chamber located between said combus tion chamber and said gasifying chamber, oil supply means substantially at the bottom of said gasifying chamber, the thirdementioned walls including a partition Wall having a nozzle and separating said centrifugal chamber from said combustion chamber, and means forming in said gasifying chamber at least one helical duct, said duct being closed along lateral sides except for air admission perforations in the second-mentioned walls so that gas flow is restricted to passage along the axis of the duct, said oil burner being characterized in that it is provided with fresh air supply means opening into the nozzle cross section.

7. The oil burner as claimed in claim 6, characterized in that said fresh air supply means is formed as a tube which traverses said burner from bottom to top.

8. The oil burner as claimed in claim 7, characterized in that the tube is provided adjacent its upper end with baiiies projecting outwardly from its peripheral surface in the same direction, and shielding the air outlet openings and that said bales are formed as tongues bent outwardly from the wall of the said tube, in a slightly upward direction, which are completed to channels by upper and lower screening surfaces.

9. The oil burner as claimed in claim 7, characterized in that the outlet end of said tube is formed as a nozzle.

l0. The oil burner as claimed in claim 7, characterized in that a valve is provided on the air inlet end of said tube.

References Cited in the le of this patent UNITED STATES PATENTS 267,478 Bangs Nov. 14, 1882 (Other references on following pagel 7 UNITED STATES PATENTS 2,253,737 Machlet Nov 26 1901 2357587 n 2,732,892 De Lancey Dec. 22, 1931 Breese Mar. 19, 1940 5 Katz Mar. 26, 194() 436,600

Millet etal V Nov. 25, 1941 Hammell Y Sept. 5, 1944 Kelly Jan. 31, 1956 FOREIGN PATENTS Great Britain Oct. 15, 1935 

